Various means have been used in the prior art to allow a subcaliber projectile to be fired from a large bore gun. Such combinations are generally used in order to give a high density projectile maximum kinetic energy effect at impact. Increasing a projectile's terminal velocity generally improves the projectile's penetration capability. Prior art sabot designs utilized kinetic energy subcaliber penetrator rounds which frequently were of cup shape or ring type design. With the development of high length-to diameter (L/D), fin stabilized, high density kinetic-energy penetration "arrow" projectiles, it became obvious that the traditional cup or push type sabots designs were inadequate. It became necessary to develop ring or push-pull type sabots which wrapped around the projectile, partially pulling and partially pushing the projectile through the launch tube. One of the problems with fin-stabilized, "arrow" projectiles and prior art ring sabot combinations has been the destructive errosion effects caused by propellant gas leakage at the interfaces between the launch tube and sabot and between the sabot and the projectile. Another problem with the prior art ring sabot designs was that they frequently failed to prevent in-bore balloting, and failed to give clean and swift discard from the subcaliber projectile.